High-pressure
Hydrogenation Reactor is the most important and critical equipment for many chemical industries, and whether its operation is stable and reliable seriously affects the operation of the whole production unit. In order to better use it, it is very necessary to understand the hydrogenation
Reactor working principle, role and procedures.
Hydrogenation reactor working principle
Hydrogenation reactor is a kind of pressure vessel, its working principle is to send the raw gas or hydrogen under pressure into a closed container to carry out the chemical reaction, and then discharge the reacted gas through the venting.
Since the pressure of hydrogenation reactor is high (generally often more than 10mpa), it is necessary to check and maintain the equipment before use. Hydrogenation plant mainly consists of four parts: heating furnace, heat exchanger, catalyst bed and
High Pressure Storage Tank.
The heating furnace consists of electric heater, steam heater and thermal oil circulation system; the heat exchanger consists of shell and tube bundle; the catalyst bed is made of stainless steel plate and carbon steel plate welded together; the storage tank consists of liquid-phase tank and gas-phase tank, in which the liquid-phase tank is used to contain the material, while the gas-phase tank is used to collect the discharged gases and sent to the purification and treatment device for further processing.
When pressurized operation, first open the power switch of electric heater and the valve of cooling water to preheat the medium temperature in the jacket to reach the set value, then open the feed valve to make the material enter the reaction chamber for heating and warming to a certain temperature, then close the feed valve and open the valve of condensate slowly to prevent the pipeline from clogging due to a sudden drop in temperature or condensation phenomenon that affects the effect of heat transfer; when the needle of the pressure gauge reaches the set value, stop the steam and adjust the pressure down to the required level. When the pressure gauge reaches the set value, stop feeding steam and reduce the pressure to the required working pressure to start normal operation.
Role of
High Pressure Hydrogenation Reactor The autoclave is generally used for reducing hydrogenolysis. The
High Pressure Reactor has a high reaction rate and reaction degree, which can effectively improve the reaction efficiency and yield. Secondly, the high pressure reactor has a low pollution rate and exhaust emission rate, which is not only favorable to environmental protection, but also can guarantee the quality of products. High pressure reactor can also be convenient and safe to control the reaction parameters and inhibit the occurrence of side reactions, improve the stability and continuity of production. High pressure reactor has low energy consumption and cost, and has a wide range of applications in a variety of chemical reactions, and more and more attention by the industry.
Hydrogenation reaction design considerations
(1) Hydrogenation reaction plant should be designed in accordance with the requirements of Class A buildings, control room, cabinet room, power substation, laboratory, office and other personnel-intensive areas shall not be arranged in the same building with the hydrogenation reaction. Pressure relief facilities should be set up in the room or part of the hydrogenation reaction with explosion risk; the pressure relief facilities should adopt non-combustible lightweight roof panels, lightweight walls and doors and windows that are easy to relieve pressure. Pressure relief area should be in line with the national standard "Building Design Fire Code". Pressure relief facilities should be set up close to the parts with explosion risk, and should avoid crowded places and major transportation roads. The ground is made of non-sparking flower material to prevent the accident caused by sparks when the iron falls to the ground.
Because hydrogen is lighter than air, the upper space of the room for hydrogenation reaction should be well ventilated; the inner surface of the roof should be leveled to avoid dead ends and prevent hydrogen from accumulating. The structural form of roof beam upturned can be used. Combustible gas detection and alarm device should be set above the hydrogenation reactor. When a large amount of hydrogen leakage or accumulation occurs, the gas source should be cut off immediately, ventilation should be carried out, and all operations that may generate sparks should not be carried out.
(2) Because most of the hydrogenation reaction adopts palladium-carbon solid catalyst, liquid flooding will be generated during the production process, and the catalyst will block the safety valve orifice throat, resulting in the failure of the safety valve or the inability to return to the seat intact after tripping, it is recommended to connect rupture discs in series in front of the safety valve of the hydrogenation reactor. The discharge pipe should be connected to the accident emergency receiving tank to avoid secondary explosion or pollution; the volume of the accident emergency receiving tank is not less than the volume of the hydrogenation reactor. The vent pipe of the hydrogen-containing tail gas should be equipped with a flame arrestor at the nozzle to prevent backfire and lead to the outdoor, and the nozzle should be 2 m above the ridge.
Because of the combustibility of hydrogen and the spontaneous combustion of the catalyst, the hydrogenation reaction system should be purged and replaced before use, and the nitrogen conversion method can be used, and an oxygen content analyzer should be installed on the hydrogenation reactor; its venting system and catalyst activation, regeneration system should be protected by nitrogen seals to avoid contact with the air.
(3) The pipes of hydrogen pipeline should be made of seamless steel pipes, and cast iron pipes are prohibited. The connection of pipes should be welded except for the connection with equipment and flange, which can be made by flange connection. Hydrogen piping, valves, couplings, etc. should not be selected and the medium of the chemical reaction of the brass material. It is necessary to strengthen the inspection of the equipment and regularly replace the pipes and equipment to prevent accidents caused by hydrogen embrittlement. Pipeline flanges, valves and other connections should be used to cross the border with metal wires to prevent static electricity buildup. Hydrogen piping shall not pass through buildings unrelated to it. Hydrogenation reaction related electrical equipment explosion-proof level should meet the requirements of "Design Code for Electric Power Installations in Explosive Hazardous Environments", and its explosion-proof level should be CT4.
Operation Regulations of High Pressure Hydrogenation Reactor
The operation procedure of a complete autoclave reaction is divided into five processes: installation, hydrogenation, sampling, hydrogen release and unloading.
(I) Installation
1.Check whether there are flammable and explosive items inside and outside the kettle, and whether there are items unfavorable to air circulation, if so, please remove them.
2.Check whether the valve and kettle are clean, if not, please wash.
3.Close all the valves, except the exhaust valve, start feeding, cover the kettle cover after feeding, pay attention to rotate the nut with even force, make sure the two diagonal screws are tightly screwed to each other, in case of air leakage after tightening.
4.Close the exhaust valve.
(B) Check the air tightness of the device
Close all the valves, cover the kettle cover, pay attention to rotating the nut should be uniform force, to ensure that the diagonal two screws screw each other to prevent air leakage after tightening. Open the inlet valve to nitrogen to 1MPa, close the inlet valve, observe the pressure change to confirm whether the device leakage.
(C) Hydrogenation
1.Check whether the valves are closed tightly.
2.Point the exhaust hose to an open and air-circulating place.
3.On the hydrogen pressure reducing valve, note that the fillet of the hydrogen pressure valve is anti-filament. Nitrogen pressure valve, on the good with soapy water to check whether the leakage, such as leakage, please re-up.
4, in the exhaust port with a vacuum to pump out the air on the liquid surface.
5, open the kettle air inlet valve, open the nitrogen pressure reducing valve nitrogen filling so that the kettle pressure P = 0.2Mpa, close the nitrogen pressure reducing valve, close the air inlet valve, keep about 2 minutes to see whether the pressure gauge pressure drop, in addition to leaning over the side of the head to listen to the valve, kettle cover leakage, such as no leakage, then slowly open the exhaust valve, inside the pressure discharge to 0.01Mpa, close the exhaust valve.
6.Repeat the operation of step 5 once.
7.Open the inlet valve, open the hydrogen pressure reducing valve, fill hydrogen to the required pressure, close the inlet valve, close the hydrogen pressure reducing valve, and then debug other parameters to the required state to make it react.
(D) Control sampling
1, every half hour to observe whether the data is normal, such as the pressure decreases, it is necessary to re-supply hydrogen.
2, hydrogen cylinder hydrogen can not be put out, must ensure that there is a certain pressure, P ≈ 0.01Mpa should be abandoned for a new bottle!
3.Take sample. Slowly open the exhaust valve, set the kettle pressure to 0.2Mpa, close the exhaust valve, slowly open the sampling valve to the reaction liquid bubbling, close the sampling valve to take a sample, and then clean the sampling port, can not let the flammable residue.
(E) Drain hydrogen
Confirm the end of the reaction, slowly discharge hydrogen to the end, pay attention to a little pressure within the exhaust valve, so as to avoid the entry of oxygen, open the inlet valve, flush nitrogen to 0.2Mpa to close the inlet valve, and then slowly open the exhaust valve, release the mixed gas inside, will be the end of the time to re-enter the nitrogen, so that the exchange of gas for three times, the gas on the liquid surface with a vacuum pump to pump out the exhaust valve, open the exhaust valve, the sampling valve, and begin to discharge the material from the bottom valve. Note that because of the oxygen easily spontaneous combustion of substances such as Pa/c, RaneyNi, so do not spill outside the container, such as spillage, please immediately use a wet towel dipped out into a bucket of water, and then a small amount of dilute acid to destroy it, immediately close the bottom valve after discharging.
(F) Unloading
After discharging the kettle, it should be cleaned immediately, and the following steps should be carried out before cleaning:
1, the reaction solvent from the exhaust valve into the kettle, clean off most of the residue, inject water half kettle stirring for 10 minutes. At this time, you can open the kettle cover to clean the inner wall of kettle.
2.When cleaning, the kettle cover and sampling valve must be cleaned, and the kettle should be slightly filled with nitrogen when there is water in the kettle.
3, temporarily unused reactor, it is best to add 70 volumes of clean anhydrous ethanol soaking kettle, you can not tighten the screws.
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